American Indian (AI) males experience profound health disparities compared to their counterparts in all other U.S. racial and ethnic groups. For example, AI men have the highest age-adjusted prevalence of type 2 diabetes (~18 percent) among U.S. men, while non-Hispanic White men have the lowest (~7 percent). In recent decades, AIs have seen a disproportionate increase in diabetes-related complications and mortality compared to all other groups, such that age-adjusted diabetes death rates in AI men are now almost twice those in White men. Several large randomized, controlled trials in non-AIs confirm that type 2 diabetes can be prevented or delayed by interventions that promote healthy lifestyles, but little empirical data exist on interventions to prevent diabetes in AI men. In the clinic-based U.S. Diabetes Prevention Program (DPP), only 55 out of 3,234 participants were AI men. Similarly, in the diabetes prevention programs in Native communities, participation by AI males is low, ranging from 33 percent to 74 percent. Many explanations have been posited for the low participation rates among men of all races in lifestyle interventions. Recruiting AI men in clinic-based programs is difficult because they tend to seek clinical care less often than women. AI men's perceptions of normative health behaviors and gender roles may also discourage participation, particularly in mixed-gender groups. Therefore, an urgent need exists for diabetes risk reduction programs tailored to the unique values and habits of AI men, with a particular focus on recruitment and retention. We are collaborating with the Mille Lacs Band of Ojibwe (Minnesota), the Indian Health Board of Minneapolis (Minnesota), and Yakama Nation and Heritage University Center for Native American Health and Culture (Washington) to develop the Strong Men, Strong Communities (SMSC) program. This is a culturally appropriate approach for AI men that targets modifiable diabetes risk factors. It uses methods adapted from successful, non-clinic based programs for other high-risk minority populations, and it incorporates elements of DPP and SDPI-DP. Our Specific Aims are to: 1) Refine the SMSC intervention with feedback from focus groups in our 3 partner communities. 2) Compare change in diabetes risk score (primary outcome) and modifiable diabetes risk factors (secondary outcomes) in the SMSC intervention and wait-list control groups. 3) Evaluate the ability of SMSC to retain 80 percent of 240 AI male participants, 21-65 years of age with no previous diagnosis of diabetes. The proposed study fills a striking gap in approaches to increase recruitment and participation in lifestyle programs that reduce diabetes risk in AI men. The proposed study will have broad implications for the ongoing epidemic of AI obesity and diabetes. Given the need to increase AI men's participation in lifestyle interventions, our findings might have substantial public health impact on tribal communities across the U.S.